Sheet profile gauging and recording system



Oct. 29, 1963 F. M. ALEXANDER ETAL 3,108,344

SHEET PROFILE GAUGING AND RECORDING SYSTEM Filed Feb. 27, 1961 r 3 Sheets-Sheet l cs l8 1 I6 20 SCANNING RECORDER I 319%?! CONTROLLER CONTROLLER 3o MOISTB E Oct 1963 F. M. ALEXANDER ETAL 3,103,844

SHEET PROFILE GAUGING AND RECORDING SYSTEM Filed Feb. 27, 1961 3 Sheets-Sheet 2 w! A 3 8. mos: 36555 H53 v2 mm. my on ms 31 Ow fiw $2 211 8 O .51 31 mm 8: gs 3s 82 v: m 2% 8w u 02 80% mwd 32A @w mw L M NH H5. a H H H H yaw QIBZSNTORS ll. (7M 97; am fi Q a Oct. 29, 1 6 F. M. ALEXANDER ETAL 3,103,344

SHEET PROFILE GAUGING AND RECORDING SYSTEM Filed Feb. 27, 1961 3 Sheets-Sheet 3 IN OUT TI T2 T5 T5 DWELL SCAN "A" owizu. DWELL SCAN "a" DWELL 'Invmrons J g/Z M 3,lltl3,344 Sl-iEET PRUFKLE GAUGING AND RECGRDHNG SYdTEh/i Frank M. Alexander and Walter H. Canter, in, Cohan bus, Ohio, assignors to industrial Nueieonics Corporation, a corporation of Ghio Filed Feb. 27, 1961, Ser. No. 91,862 7 tllairns. (CE. 34d=-46) This invention relates generally to systems for recording process information and more particularly to a novel method and means for recording dimensionally-related variations in one or more physical properties of a material.

Many industrial processes are concerned with forming raw material into a final salable product. Paper machines, steel rolling mills, plastic extruders, and cigarette factories are but an exemplary few of these processes. All of these processes require monitoring of their various phases to assure a product well Within a desired specification. For example, in the paper-making process, operating personnel must be constantly aware of ever-changing variables such as basis weight and moisture content of the paper sheet at various points. Only when this information is provided in a concise manner which may be readily interpreted, will the process be operated in the most efficient manner possible.

In the past, operating personnel have been required to observe a number of wildly gyrating indicating needles or confusing chart traces in order to determine the value of a process variable at a particular portion of sheet being processed. It has been even more diificult to investigate the correlation, if any, of the various process variables between the same portions of the sheet. And oftentimes a single point measurement of the sheet is not at all indicative of conditions existing at other points. It has been necessary to employ a separate recorder for every variable being measured.

To overcome these disadvantages, the present invention provides gauges for traversing the cross-sheet dimension of a paper sheet to measure variables such as the basis weight and moisture content. A novel chart recorder is constructed with a chart drive that moves in accordance with the measured variable and a single pen drive that displaces a two-pen carriage across the chart in accordance with the movement of the traversing gauge across the paper sheet. The measuring and recording system is programmed to record the variations in one variable and then the other by selectively lowering one pen or the other and to present the traces in dimensional-Wise coincidence with suitable identifying indicia.

Accordingly, it is a primary object of the present invention to provide a system for recording dimensionallyrelated process variables.

It is another object of the present invention to provide a recording system that presents process information in a manner which may be readily interpreted by operating personnel.

It is also an object of the present invention to provide a recording system that is considerably cheaper in initial cost and less expensive to maintain in operating condition than similar devices used heretofore.

It is yet another object of the present invention to provide a recording system that is simple to construct.

These and other objects and features of the present invention will become more apparent when the following description is taken in conjunction with the drawings, in which:

PEG. 1 is a diagrammatic view of a measuring and recording system constructed in accordance with the present invention;

FIG. 2 is a partial perspective View, partly diagrammatic, of a measuring and recording system for a paper-making add process comprising a preferred embodiment of the present invention;

FIG. 3 is a schematic diagram partly diagrammatic showing the bridge circuitry of the recorder shown in FIG. 2;

FIG. 4 is a schematic diagram of a control circuit for properly sequencing the operation of the measuring and recording system shown in PEG. 2.

FIG. 5 is a sketch useful in explaining the operation of the present invention;

FIG. 6 is a front elevational view of a pen-lifting assembly used in the recorder shown in FIG. 2;

FIG. 7 is a sectional view of FIG. 6; and

FIG. 8 is an enlarged end elevational view of an actuator for the pen-lifting assembly shown in FIG. 6.

Referring to the drawings, and specifically to FIG. 1, the present invention provides apparatus for presenting information from both a basis Weight gauge '10 and a moisture gauge '12 on a movable chart 14. A recorder controller 16 is connected to a scanning controller 18 which moves the gauges ll and 12 back and forth over a sheet to be measured. The mechanical linkage coupling the controller 18 to the gauges 10 and '12 is represented by the dotted lines 24 and 26. A supply 23 supplies power for the controller 1%.

A recorder sequentially provides a first trace 30 indicative of variations in basis Weight of the sheet being measured and a second trace 32 indicative of variations in moisture content of the sheet. The resulting graph depicts a dimension of the sheet being measured, such as the width, in the x-direction and instantaneous values of the measured variable in the y-direction. Furthermore, the traces 39 and 32 are arranged in dimensional coincidence so that both the basis weight and the moisture content at any point across the sheet is readily observable. Since there is usually a desired or target value for each variable, it is desirable to draw a horizontal line after each curvilinear trace for purposes of comparison.

Referring to FIG. 2, a traversing gauge mounting bracket 44% is shown in non-contacting engagement with a traveling paper sheet 38. The mounting bracket consists of an upper arm l2 and a lower arm 44 which is slidably mounted on a rail 46. The lower arm carries a radiation source housing 48 at the end thereof. While the upper arm carries a radiation detector housing 50 in vertical alignment with the radiation source, a conductor 52 carries an electrical signal generated in accordance with wellknown principles of radiation absorption and proportional to the basis Weight of the sheet 38. On the downstream side of the detector housing 50 is mounted a moisture detector 54 such as that disclosed in Serial No. 41,975 or others commercially marketed. The detector 54 provides over conductor 56 an electrical signal representative of sheet moisture.

The bracket to is driven by a reversible traversing motor so through a chain-and-sprocket assembly. In and outlirnit switches 62 and 64 are mounted on the rail 46 and are actuated by the gauge mounting bracket 46 whenever the edges of the sheet 38 are embraced by the ends of the arms 42 and 44. The scanning controller 18 not only energizes the traversing motor 60 but also provides for a dwell time at the end of each scan.

The recorder 2i) includes a chart roll on and a dual pen carriage 68 slidably mounted on a guide rod '79. The twopen recorder 2% is conventional and may be similar to that manufactured and commercially marketed. However, it is noted that the pens are not independently movable across the chart 19 as is usually the case. The pens are mounted one behind the other, are integrally movable with the carriage 63, and are filled with two distinguishably colored inks such as red and blue.

The present invention provides apparatus for controlling recorder 29 to obtain the aforesaid traces. A single pen drive is coupled to the traversing motor 60 to move the carriage 68 back and forth across the chart paper 14. Therefore, each position of the carriage across the chart corresponds to a particular location of the gauge housings 5% or 54 across the paper sheet 38. The instantaneous displacement of the chart roll 65 is determined by a function selecting the chart controller unit '72. The input to unit 72 comprises the weight-functional and moisturefunctional signals carried by lines 52 and 56 respectively. Unit '72 is connected to the scanning controller 18 and determines which signal will be read out during any given scan of the gauge mounting bracket 4t A pen selector '74 serves to position only one of the pens in marking relationship with the chart 14 at one time by actuating a pen lifting solenoid 76. The pen selector switches from one pen to the other preferably at the end of each out scan.

Briefly, since a more detailed description ofoperation appears hereinafter in reference to FIGS. 3 and 4, the sequence of events occurs in the following order: Assume that the red marking pen initially engages the chart 14.

The gauge mounting bracket begins an out scan in the direction indicated. Basis weight variations in the sheet cause the chart roll 56 to rotate and counter-rotate. As the pen carriage moves across the chart 14 a profile of the cross-sheet variations in basis Weight appears as a curvilinear trace 76. When the gauge mounting bracket has completed its traverse of the sheet 33 it stops. Whereupon, pen selector 74 changes to the blue marking pen. The chart roll 66 is rotated until the blue pen is positioned at a desired or target value for the basis weight of the sheet being measured. As the gauge mounting bracket starts a return or in scan after a brief dwell time, the position of the chart roll 66 is maintained. A horizontal line 78 indicative of the target value for the basis weight of the sheet 34 is provided during the in scan of the gauge mounting bracket 49.

At the completion of the in scan, another dwell of the mounting bracket is initiated and chart 14 is unidirectionally advanced a predetermined distance. When the dwell time has ela sed, the function switching and chart controller unit '72 selects moisture-functional signals on line 56 to be read out. Now, the chart roll 66 responds to variations in the moisture content of the sheet 33 as another out scan is initiated. Curvilinear trace 80 is drawn on the chart. During the dwell time, at the completion of the second out scan, the pen selector removes the blue pen from the chart and places the red pen in marking registration therewith. Chart roll 66 assumes an angular position relative the red pen nib corresponding to a target value for the moisture content of the sheet 38. And this new position of roll 66 is maintained during the second in scan.

The sequence is automatically repeated during succeeding scans of the gaugemounting bracket 40. With this scheme the pens are continually being used so they do not clog up; each curvilinear trace is readily distinguishable from the other; and comparisons of the measured'variable'with its target value are facilitated by using a different color for each trace. It may be desirable to observe only one function at a time. Apparatus is described hereinafter for selecting three different modes of recorder readout: basis weight only, moisture only, or alternately both. Regardless of the mode, the pen selector 7d switches from one pen to the other to continue the aforesaid advantages. Detailed circuitry is shown in FIGS. 3 and 4 for accomplishing the objects of the present invention. It is noted that each relay coil is given a reference numeral and contacts of a given relay are labeled with the reference numeral of the actuating coil followed by a lower case letter.

' A different lower case letter is used to distinguish between different contacts of the same relay.

Referring now to H63. 3 and 4, for convenience the circuit is divided into several different sections, each lad beled with a different Roman numeral. In FIG. 3, section I is a gauge position indicator bridge circuit and section II is a chart drive bridge circuit. In FIG. 4, section III includes a gauge traversing motor and the relay control circuit therefor. Section IV is a dwell timer for initiating both the out scan and the in scan of gauge mounting bracket 40 as well as the sequencing of the operation of recorder 20.

Generally, sections V through X control the switching of the various slidewires and target potentiometers into the bridge circuit of section If and the operation of the pen solenoid. Specifically, section V connects one of the target potentiometers into the bridge at the end of each scan. Section V1 is a chart clutch solenoid for decoupling the chart roll 66 from its drive means during return or in scans. Section VII comprises a chart slidewire arm centering relay. Section VIII rotates the chart roll 66 through a predetermined angular displacement at the end of each return scan. The function to be read out on recorder 24] is selected by a rotary stepper included in a profile selecting section IX. And section X comprises a pen selecting solenoid circuit operating in conjunction with sections V and IX which changes marking pens.

The gauge position indicator bridge section I comprises a multi-turn potentiometer 81 and a recorder pen slidewire 82 connected in parallel by means of a pair of endadjusting potentiometers 84 and 86. The movable arms of the potentiometers 81 and slidewire 82 are connected to the input of a servo amplifier 88. Operating potential for the bridge is provided by lines 9% and 92 connected to the secondary of a transformer 94. The primary of transformer 94 is connected to a source of AC. voltage generally shown at 96. The arm of potentiometer 81 is a mechanically linked as at 98 to the gauge traversing mogauge traverses the sheet 38, pen motor 1% moves the pen slidewire arm to diminish the input to the servo amplifier 88. An indicator 102 may be mounted on the pen carriage 68 to be in registration with a scale 1694 of a length corresponding to the lateral dimension of sheet 38. It can be seen that the indicator E02 follows the position of the'gauge mounting bracket 44) back and forth across the sheet 38.

The chart drive is coupled to a similar bridge circuit. Referring to section II, there is included a chart slidewire 106, a basis weight slidewire 1%, a moisture slide wire 114 a basis weight target potentiometer 112 and a moisture target potentiometer 114. A pair of equivalent resistances 116 and 118 are connected between lines and 92, one resistance having a variable tap 116a. A servo amplifier 120 actuates a chart drive servo motor 1-22 mechanically coupled as at 12.4 to the movable chart slidewire arm 106a and a shaft 126. The chart roll 66 may be decoupled from the shaft 126 by'means of an electromechanical clutch 128. One input of servo amplifier 12.0 is connected to the chart slidewire arm 106a.

The other input may be selectively connected in a manner described hereinafter to the movable arms of the slidewire MP8, 11 0, the target 'pot entiometers 112, 114,

'variable resistor 116 or to the junction of resistors 116 and 118 at an equal potential with respect to both lines 90 and 92. The chart motor 122 positions the chart slidewire arm ltlfia to diminish the input to servo amplifier 12d.

A basis weight measuring servo drive the arm of slidewire res. and a moisture measuring servo 132 may be used to drive the arm of slidewire 110. 7 Reference may be had to US. LettersPatent 2,790,945

for a' description of the basis weight measuring servo employed at 180. The construction of the moisture meas- 130 maybe used to if arsen l-a uring servo 132 will become immediately apparent. Briefly, each slidewire arm is positioned across the slidewire resistance associated therewith in accordance with the measured value of the respective physical properties of the sheet 38.

With reference now in detail to FIG. 4, power source 96 provides operating potential for the relays via lines 14d and 14-2. A forward relay 144- and a reverse relay this in section ll-I control the direction of rotation of traversing motor st). A dwell timer 148 such as manufactured and marketed by Eagle Signal Company, Moline, Illinois, under the trade name Cycle-Flex is included in section IV. Sections V through VIII include a target relay 150 energized only during out scans by the forward relay 14 in section III, the chart clutch solenoid 128, a centering relay 152 and a chart stepping relay 154. Section IX comprises a conventional rotary stepper having an actuating coil 155, a plurality of alternately commonly connected contacts idea-15min and a rotor arm 158. A profile selecting relay lot? may be connected between lines Md and 1 32 by the rotor arm 158.

The explanation of the operation of the system is facilitated by reference to the sketch shown in FIG. 5 wherein two successive scans A and B are represented. Moving to the right of the diagram represents an out scan, while moving to the left represents an in scan. Reference is made hereinafter to operations occurring at times T T The time at which the gauge assumes a given position is denoted on the diagram at appropriate points.

At the beginning of a sequence, time T in-limit switch contacts 62a energize the motor forward control relay 144 which is held by contacts 144a. Contacts 1441) close to start the gauge traverse and contacts 1440 close to energize the target relay 1%. in the chart drive bridge section II, contacts 150a open and contacts 1563b close to connect the basis weight slidewire 1% into the servo amplifier 12h. Contacts 1560 open and contacts 156d close to keep the pen solenoid 76 energized. For purposes of explanation, it is assumed that whenever the solenoid it: is energized the red marking pen scribes the chart 14'. Conversely, whenever solenoid 76 is deenergized, the blue marking pen scribes the chart 14-. The chart slidewire arm 166a follows the movements of the arm of the slidewire Hi8. Therefore, a cross-sheet basis weight profile is drawn on the chart.

At time T when the gauge attains its full-out position, out-limit switch contacts 64a start the dwell timer 143. Timer contacts 143a immediately open to release the motor forward control relay. Contacts 1 34b open to stop the traversing motor 6'9. Out-limit switch contacts 6412 open to drop the target relay 15d, and the pen solenoid 76 is deenergized since contacts 15%;! open when the target relay is deenergized. Accordingly, the blue pen is lowered on the chart 14. Now the input of servo amplifier 124} is connected to the arm of the basis weight target potentiometer 112 through contacts 15th: and Mile. The chart slidewire arm lltida positions according to the setting of target potentiometer 112 and the position of the chart roll 66 is indicative of the target value for basis weight.

After a brief dwell time, timer 148 times out to close contacts 148a. The motor reverse control relay 1% picks up through out-limit switch contacts 64d which are closed when the mounting bracket 1-h dwells in the full-out position. Contacts 146a serve to hold relay 146 energized. Contacts Mfib open to deenergize the chart clutch solenoid 128. Since the chart cannot move, the blue pen follows the returning gauge drawing a straight line at the basis Weight target. While the gauge returns, contacts Mod close to energize the chart slidewire arm centering relay T52. Contacts 152a open and contacts 152i; close to connect the junction of resistors 116 and M3 to the input of servo amplifier 112i). Whereupon servomotor 122 positions the chart slidewire arm Mina 6 at the electrical midpoint of the chart slidewire 106. This procedure is necessary to provide a positional datum reference from which the chart may be advanced at the end of each in scan. As soon as the gauge mounting bracket clears the out-limit switch 64 contacts 64a open to reset the dwell timer 148.

Eventually, the gauge attains the full-in position at time T The in-limit switch 62, is actuated by the gauge mounting bracket it? and contacts 62b close. Dwell timer 14$ begins timing. Timer contacts 148a open once again at the start of the timing period, thereby dropping relay 146 and stopping the gauge traversing motor 60. The chart clutch solenoid 123 is energized by contacts 1450 enabling the motor 122 to move the chart 14. Contacts 123a open to drop out the chart slidewire arm centering relay 152. Contacts 12 b close in series with inlimit contacts 62c to energize the chart stepping solenoid T54. Contacts 154a open and contacts 15% close to connect the movable arm 116a into the input of the servo amplifier 120. The servomotor 122 will advance the chart 1 until the arm Tilda assumes a potential equivalent to that existing on the arm of resistor 116.

At time T timer 143 times out, closing contacts 143a to start scan B. The motor forward control relay 144 is energized. In addition, timer contacts 1431) in series with the stepper coil 156 and closed in-limit switch contacts 62d close to advance the rotor arm 158 onto contact 156b, energizing the profile selector relay 16d. Contacts 16% close and contacts 15% open. The pen solenoid 76 tends to pick up; however, contacts 159a open to remove power when the target relay 156 is energized through contacts 144a. The pen solenoid 76 remains deenergized and the blue pen continues to scribe the chart lid. As the gauge mounting bracket ltl moves away from the full-in position the in-limit switch is no longer actuated. Switch contacts 62b, 62c, and 62d all open to respectively reset dwell timer 148, to drop the chart stepping relay 15 i and to remove power from the stepper coil 156.

As soon as the gauge begins scan B, since relay 15%) is again energized, contacts 15Gb blose. However, now since the profile selector relay res is energized, it is the arm of the moisture slidewire which is connected to the input of servo amplifier 129 via closed contacts 16%. Therefore, during the out scan of B the movements of the arm of slidewire iii are traced in blue upon the chart.

The gauge mounting bracket 49 reaches the full-out position at time T The target relay is deenergized and it is the arm of the moisture target potentiometer 114 which is connected to the input of servo amplifier 12% through contacts 150a and profile selector relay contacts 16% The pen solenoid 76 becomes energized as relay contacts 1590 close in series with contacts 160a of the energized profile selector relay. The red pen en ages the chart to draw the moisture target value upon the chart 1 subsequent to the chart roll decoupling operation described hereinabove. Dwell timer 148 times out to start the in scan of B at time T Contacts ltd-8b close but the stepper 156 cannot pulse since in-limit switch contacts 62d remain open. Relay 156 centers the arm M3611 of the chart slidewire 1%.

When the full-in position of scan B is attained at time T the chart roll 65 is connected to chart motor 122 through the clutch 128 and the chart is advanced in accordance with the position of the arm 116a of variable resistor 116. At the end of the dwell time, the stepper coil 156 is pulsed through timer contacts 148b and closed in-limit contacts 62d. The stepper rotor arm 158 advances one position to contact 156a Profile selector relay 169 is dropped. The pen solenoid 76 tends to drop out when contacts 166a open, but it is picked up by contacts 15611 which close at the start of the next in scan. The red pen remains on the chart 14 and the initial circuit conditions exist as the foregoing sequence is automatically repeated.

The operation of the circuit has been described wherein,

the arm of either the basis weight slidewire 108 or the moisture slidewire llllil. Likewise deck 162B locks onto the arm of either the basis weight target potentiometer 112 or the moisture target potentiometer Illi. Therefore, regardless of the state of the profile selector relay loll, only one function or the other is read out. Referring to the pen selector section X, with the arm of switch deck 162C in position 2 the pen solenoid 76 is energized during out scans and deenergized during in scans. In position 3, the switch 162 servesto deenergize the pen solenoid "/6 during out scans and to energize it during in scans. It is observed that the profile selector 160 has no function when switch 162 is thrown to either position 2 or position 3. 7

Referring to FIGS. 6, 7, and 8, the mechanical construction of the pen lifting mechanism of the present invention is now described. A pair of spaced end members 164 and res are joined by a pair of spacers 168 and 17%, each provided with a shoulder and a threaded portion at opposite ends thereof. Nuts as at 172', serve to secure the spacers 168, 1'70 to the end members 16 i, 166. Pen lifting rods 174 and 176 are inserted between the end members and the entire assembly is rotatably mounted between walls 178, 18b of the recorder housing.

The assembly may be provided with end axles 182, 18 i journaled in bearings as at 186 located in each of the walls 178, 18h. 7

Referring to FIG. 7, in two-pen recorders it is customary to mount the pens by providing a pair of offset guide rods 1%, 1% for slidably mounting a red pen carriage 192, and a blue pen carriage 194-. A red pen 1% is of considerably greater length than a blue pen 1% to extend in front thereof. The carriages 192, 194 are normally driven through individual pulley and cord arrangements (not shown); however, with the system of the present invention, the carriages are driven as a unit.

The pen lifting rod 17 is passed under red pen 1% and lifter rod 176 is passed under blue pen 1%. With reference now to FIG. 8, the pen solenoid 76 is preferably of the rotary type. An actuating stud Ztltl extends from the pen solenoid "76 to engage a slot provided in the end member 164%. Slots 2th! and 2% may be provided to removably support the pen lifter rods 17 i,

376. When the solenoid is energized the stud 2% moves to the dotted line position Zlltla, whereupon the lifter rods 174, 176 are respectively lowered and raised.

Although there is shown and described a preferred embodiment of the present invention, modifications may be made without departing from the true scope and spirit of the invention.

What is claimed is:

1; Apparatus for recording the profile characteristic of at least one physical property of a material with a movable chart and marking stylus movable with respect thereto, comprising means for measuring the variations in said physical property across one dimension of said material in the plane of said profile, means for displacing said marking stylus across said chart to correspond with the point of measurement across said dimension, means for positioning said chart in accordance with the magnitude of said measured physical property, means for scribing said chart with a colored ink, means for generating a target signal proportional to a desired value of said measured property, means for positioning said chart in ccordance with said target signal, means for displacing said marking stylus in the opposite direction after said entire material dimension has been measured, means for scribing said chart with a different colored ink to provide a trace of said target value, and means for repeating said steps. 2. Apparatus as set forth in claim 1 further including means for alternately measuring and recording a second physical property of said material, means for scribing said chart marking of said second physical property with said same color as said target trace of said first physical property, and means for presenting said chart markings in vertical alignment on said chart.

3. In the combination of a traversing gauge and a strip chart recorder for providing successive plots of the profile of a variable measured by said gauge across the width of a sheet, said recorder having an indicator movable across said chart in synchronism with a corresponding traversing movement of said gauge across said sheet width, said chart being movable orthogonally with respect to said indicator movement to register changes in the measured value of said variable, the improvement comprising a servomechanism for driving said chart to a position proportional to a signal applied to said servomechanism, means controlled by said gauge for generating a first signal indicative of the measured value of said variable, manually adjustable means for generating a second signal indicative of a desired value of said variable, means for generating a third signal-indicative of a selected separation distance along said chart between said successive plots, programmed switching means for applying said first, second and third signals seriatim to said servomechanism, and means energized in response to said gauge reaching the limit of said traversing movement across said sheet width for advancing said programmed switching means.

4. In the combination of a traversing gauge and a strip chart recorder for providing successive plots of the pro prising a servomechanism, a chart drive mechanism, a

clutch connecting said servomechanism to said chart drive mechanism whereby said chart is driven to a position proportional to a signal applied to said. servomechanism, means controlled by said gauge for generating a first signal indicative of the measured value of said variable, manually adjustable means for generating, a second signal indicative of a desired value of said variable, means for generating a reference signal indicative of an index position of said servomecham'sm, means for generating a third signal indicative of a selected separation distance along said chart between said successive plots, programmed switching means for applying said first, second, reference and third signals individually and in a sequence to said servomechanism, means energized in response to said gauge reaching the limit of said traversing movement across said sheet width for advancing said programmed switching means, and means controlled by said programmed switching means for disen aging said clutch while at least one of said second, third and reference signals is applied.

5. in the combination of a traversing gauge and a strip chart recorder .for providing successive pl ts of the profile of a variable measured by said gauge across the width of a sheet, said recorder having an indicator movable across said chart in synchronism with a corresponding traversing movement of said gauge across said sheet width, said chart being movable orthogonally with respect to said indicator movement to register changes in the measured value of said variable, the improvement comprising a servomechanism for driving chart to a position pro portional to a signal applied to said servomeohanism,

means controlled by said gauge for generating a first signal indicative of the measured value of said variable, manually adjustable means for generating a second signal indicative of a desired value of said variable, means for generating a third signal indicative of a selected separation distance along said chart between said successive plots, programmed switching means for applying said first, second and third signals seriatim to said servomechanism, means energized in response to said gauge reaching the limit of said traversing movement across said sheet width for advancing said programmed switching means, and a delay timer interconnected with said programmed switching means for delaying said advancing thereof to permit said serv-omechanism to come to rest in response to one of said signals before a succeeding signal is applied.

6. In the combination of a traversing gauge and a strip chart recorder for providing successive plots of the profile of a variable measured by said gauge across the width of a sheet, said recorder having an indicator movable across said chart in synchronism with a corresponding traversing movement of said gauge across said sheet width, said chart being movable orthogonally with respect to said indicator movement to register changes in the measured value of said variable, the improvement comprising a servomechanism for driving said chart to a position proportional to a signal applied to said servomechanism, means controlled by said gauge for generating a first signal indicative of the measured value of said variable, manually adjustable means for generating a second signal indicative of a desired value of said variable, means for generating a third signal indicative of a selected separation distance along said chart between said successive plots, programmed switching means for applying said first, second and third signals seriatim to said servomechanism, means energized in response to said gauge reaching the limit of said traversing movement across said sheet width for advancing said programmed switching means, a pair of chart marking elements carried by said indicator and alternately engageable with said chart to mark the same with one of two visually distinguishable traces, and means controlled by said programmed switching means for interchanging the engaged and disengaged positions of said pair on switching from said first to said second signal applied to said servomechanism.

7. In the combination 'of first and second traversing gauges and a strip chart recorder for providing successive plots of the profiles of first and second variables meas ured by said gauges across the width of a sheet, said recorder having an indicator movable across said chart in synchronisrn with a corresponding traversing movement of said gauges across said sheet width, said chart being movable orthogonally with respect to said indicator movement to register changes in the measured values of said variables, the improvement comprising a servomechanism for driving said chart to a position proportional to a signal applied to said servomechanisrn, means controlled by said gauges for generating first and second signals respectively indicative of the measured values of said first and second variables, manually adjustable means for generating third and fourth signals respectively indicative of desired values of said first and second variables, programmed switching means for applying said first, third, second and fourth signals seriatim to said servomechanism, means energized in response to said gauges reaching the limit of said traversing movement across said sheet width for advancing said programmed switching means, a pair of chart marking elements carried by said indicator and alternately engageable with said chart to mark the same with two visually distinguishable traces, and means controlled by said programmed switching means for interchanging the engaged and disengaged positions of said pair on switching from said first to said third and from said second to said fourth of said signals applied to said servomechanism.

References Cited in the file of this patent UNITED STATES PATENTS 2,445,272 Keegan July 13, 1948 2,579,831 Keinath Dec. 25, 1951 2,665,964 Olah et a1 Ian. 12, 1954 2,909,660 Alexander Oct. 20", 1959 2,939,757 MacDonald et al June 7, 1960 

1. APPARATUS FOR RECORDING THE PROFILE CHARACTERISTIC OF AT LEAST ONE PHYSICAL PROPERTY OF A MATERIAL WITH A MOVABLE CHART AND MARKING STYLUS MOVABLE WITH RESPECT THERETO, COMPRISING MEANS FOR MEASURING THE VARIATIONS IN SAID PHYSICAL PROPERTY ACROSS ONE DIMENSION OF SAID MATERIAL IN THE PLANE OF SAID PROFILE, MEANS FOR DISPLACING SAID MARKING STYLUS ACROSS SAID CHART TO CORRESPOND WITH THE POINT OF MEASUREMENT ACROSS SAID DIMENSION, MEANS FOR POSITIONING SAID CHART IN ACCORDANCE WITH THE MAGNITUDE OF SAID MEASURED PHYSICAL PROPERTY, MEANS FOR SCRIBING SAID CHART WITH A COLORED INK, MEANS FOR GENERATING A TARGET SIGNAL PROPORTIONAL TO A DESIRED VALUE OF SAID MEASURED PROPERTY, MEANS FOR POSITIONING SAID CHART IN ACCORDANCE WITH SAID TARGET SIGNAL, MEANS FOR DISPLACING SAID MARKING STYLUS IN THE OPPOSITE DIRECTION AFTER SAID ENTIRE MATERIAL DIMENSION HAS BEEN MEASURED, MEANS FOR SCRIBING SAID CHART WITH A DIFFERENT COLORED INK TO PROVIDE A TRACE OF SAID TARGET VALUE, AND MEANS FOR REPEATING SAID STEPS. 